gianfar: Enable padding and Optimize the frame prepended bytes handling

The eTSEC can prepend up to 32 bytes to a received frame, usually for the
purpose of aligning the IP address to a word boundary, so this turns it on.

While we're in there, make the handling of the pre-frame bytes (padding and
Frame Control Block) cleaner.

Signed-off-by: Dai Haruki <dai.haruki@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c
index 6dc9361..9057a1d 100644 (file)
--- a/drivers/net/gianfar.c
+++ b/drivers/net/gianfar.c
@@ -131,7 +131,8 @@ static void gfar_netpoll(struct net_device *dev);
 #endif
 int gfar_clean_rx_ring(struct net_device *dev, int rx_work_limit);
 static int gfar_clean_tx_ring(struct net_device *dev);
-static int gfar_process_frame(struct net_device *dev, struct sk_buff *skb, int length);
+static int gfar_process_frame(struct net_device *dev, struct sk_buff *skb,
+                             int amount_pull);
 static void gfar_vlan_rx_register(struct net_device *netdev,
                                struct vlan_group *grp);
 void gfar_halt(struct net_device *dev);
@@ -210,6 +211,7 @@ static int gfar_of_init(struct net_device *dev)
                        FSL_GIANFAR_DEV_HAS_COALESCE |
                        FSL_GIANFAR_DEV_HAS_RMON |
                        FSL_GIANFAR_DEV_HAS_MULTI_INTR |
+                       FSL_GIANFAR_DEV_HAS_PADDING |
                        FSL_GIANFAR_DEV_HAS_CSUM |
                        FSL_GIANFAR_DEV_HAS_VLAN |
                        FSL_GIANFAR_DEV_HAS_MAGIC_PACKET |
@@ -1668,59 +1670,38 @@ static inline void gfar_rx_checksum(struct sk_buff *skb, struct rxfcb *fcb)
 }
 
 
-static inline struct rxfcb *gfar_get_fcb(struct sk_buff *skb)
-{
-       struct rxfcb *fcb = (struct rxfcb *)skb->data;
-
-       /* Remove the FCB from the skb */
-       skb_pull(skb, GMAC_FCB_LEN);
-
-       return fcb;
-}
-
 /* gfar_process_frame() -- handle one incoming packet if skb
  * isn't NULL.  */
 static int gfar_process_frame(struct net_device *dev, struct sk_buff *skb,
-               int length)
+                             int amount_pull)
 {
        struct gfar_private *priv = netdev_priv(dev);
        struct rxfcb *fcb = NULL;
 
-       if (NULL == skb) {
-               if (netif_msg_rx_err(priv))
-                       printk(KERN_WARNING "%s: Missing skb!!.\n", dev->name);
-               dev->stats.rx_dropped++;
-               priv->extra_stats.rx_skbmissing++;
-       } else {
-               int ret;
+       int ret;
 
-               /* Prep the skb for the packet */
-               skb_put(skb, length);
+       /* fcb is at the beginning if exists */
+       fcb = (struct rxfcb *)skb->data;
 
-               /* Grab the FCB if there is one */
-               if (gfar_uses_fcb(priv))
-                       fcb = gfar_get_fcb(skb);
-
-               /* Remove the padded bytes, if there are any */
-               if (priv->padding)
-                       skb_pull(skb, priv->padding);
+       /* Remove the FCB from the skb */
+       /* Remove the padded bytes, if there are any */
+       if (amount_pull)
+               skb_pull(skb, amount_pull);
 
-               if (priv->rx_csum_enable)
-                       gfar_rx_checksum(skb, fcb);
+       if (priv->rx_csum_enable)
+               gfar_rx_checksum(skb, fcb);
 
-               /* Tell the skb what kind of packet this is */
-               skb->protocol = eth_type_trans(skb, dev);
+       /* Tell the skb what kind of packet this is */
+       skb->protocol = eth_type_trans(skb, dev);
 
-               /* Send the packet up the stack */
-               if (unlikely(priv->vlgrp && (fcb->flags & RXFCB_VLN))) {
-                       ret = vlan_hwaccel_receive_skb(skb, priv->vlgrp,
-                                                      fcb->vlctl);
-               } else
-                       ret = netif_receive_skb(skb);
+       /* Send the packet up the stack */
+       if (unlikely(priv->vlgrp && (fcb->flags & RXFCB_VLN)))
+               ret = vlan_hwaccel_receive_skb(skb, priv->vlgrp, fcb->vlctl);
+       else
+               ret = netif_receive_skb(skb);
 
-               if (NET_RX_DROP == ret)
-                       priv->extra_stats.kernel_dropped++;
-       }
+       if (NET_RX_DROP == ret)
+               priv->extra_stats.kernel_dropped++;
 
        return 0;
 }
@@ -1733,13 +1714,17 @@ int gfar_clean_rx_ring(struct net_device *dev, int rx_work_limit)
 {
        struct rxbd8 *bdp;
        struct sk_buff *skb;
-       u16 pkt_len;
+       int pkt_len;
+       int amount_pull;
        int howmany = 0;
        struct gfar_private *priv = netdev_priv(dev);
 
        /* Get the first full descriptor */
        bdp = priv->cur_rx;
 
+       amount_pull = (gfar_uses_fcb(priv) ? GMAC_FCB_LEN : 0) +
+               priv->padding;
+
        while (!((bdp->status & RXBD_EMPTY) || (--rx_work_limit < 0))) {
                struct sk_buff *newskb;
                rmb();
@@ -1767,12 +1752,22 @@ int gfar_clean_rx_ring(struct net_device *dev, int rx_work_limit)
                        dev->stats.rx_packets++;
                        howmany++;
 
-                       /* Remove the FCS from the packet length */
-                       pkt_len = bdp->length - 4;
+                       if (likely(skb)) {
+                               pkt_len = bdp->length - ETH_FCS_LEN;
+                               /* Remove the FCS from the packet length */
+                               skb_put(skb, pkt_len);
+                               dev->stats.rx_bytes += pkt_len;
+
+                               gfar_process_frame(dev, skb, amount_pull);
 
-                       gfar_process_frame(dev, skb, pkt_len);
+                       } else {
+                               if (netif_msg_rx_err(priv))
+                                       printk(KERN_WARNING
+                                              "%s: Missing skb!\n", dev->name);
+                               dev->stats.rx_dropped++;
+                               priv->extra_stats.rx_skbmissing++;
+                       }
 
-                       dev->stats.rx_bytes += pkt_len;
                }
 
                priv->rx_skbuff[priv->skb_currx] = newskb;